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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 29, No 4, July/August 2018
254
AFRICA
Diagnosis: coarctation of the aorta in older
patients
Although the diagnosis of coarctation of the aorta in older
patients is easy, the diagnosis is often missed or delayed. In fact,
even in older children, coarctation of the aorta is missed in about
85% of coarctation patients referred to a hospital for murmurs
or hypertension.
12,14-16
In these patients, the left ventricle has adapted to the pressure
load with hypertrophy, and lower body perfusion is achieved
by hypertension in the upper aorta. Most are asymptomatic
until later in life, although a few may have pain on walking
(intermittent claudication). If left untreated, 50% die under 30
years of age and few survive beyond 50 years of age. Death is due
to congestive heart failure, dissection and rupture of the aorta,
ruptured berry aneurysm in the cerebral circulation, or infective
endocarditis.
The clinical diagnosis is based on finding signs of left
ventricular hypertrophy, hypertension in the upper body, weak
and delayed femoral arterial pulses, and upper body collateral
circulation.
•
Left ventricular hypertrophy is appreciated by a forceful,
heaving apical thrust in systole.
•
Blood pressure should be taken with an appropriate-sized
cuff in both arms because the left subclavian artery is often
hypoplastic or distal to the coarctation, and in more than 1%
of people, the right subclavian artery is aberrant and could
originate below the coarctation. In these people the pressure
will be higher in the left than the right arm.
•
If the arm pressure is high, then feel the femoral pulses. In
coarctation of the aorta they are weaker than the radial
pulses, and when felt simultaneously with the radial pulse, the
femoral pulse is delayed. Confirmation is obtained by obtain-
ing a leg blood pressure with an appropriate-sized cuff.
•
Collateral arteries are perceptible in over 50% of these
patients, and are prominent over the edges of the scapulae.
•
An ejection-type systolic murmur may be heard at the base,
and between the spine and the left scapula.
•
Confirmation of the diagnosis can be obtained by a chest
radiogram that will show the aortic indentation at the coarc-
tation site (three sign) and rib notching of the lower ribs due
to enlarged intercostal arteries. Echocardiography is indicated
if additional cardiac lesions are suspected.
Treatment
There are two main treatment choices: surgery or balloon dilatation
with stenting.
17,18
A variety of surgical procedures has been used, but
most common are mobilising the aorta, excising the region around
the coarctation and reconnecting the two ends, or mobilising the
aorta, excising the region around the coarctation and connecting
the descending aorta to the underside of the aortic arch. The
latter is the preferred technique in infants with a hypoplastic arch
because it allows reconstruction of the aortic arch.
The operative mortality rate is very low. There is a small
incidence of paraplegia with surgery unless precautions are
taken to prevent spinal cord ischaemia. With current surgical
methods there is a 3–5% chance of re-coarctation. Surgery in
older adults has a higher mortality rate because of an abnormal
aortic wall and the development of huge, thin-walled intercostal
aneurysms.
An alternative is to dilate the coarctation with a balloon and
then insert a stent to prevent the dilated region from narrowing
due to elastic recoil. Usually infants are treated surgically because
they are too small for introducing the stent on a catheter, whereas
balloon dilatation and stenting are usually used in adults and
for treating re-coarctation. All procedures carry a small risk of
aneurysm formation.
Prognosis
In general, the results are good, although coarctation patients
had a greater and earlier incidence of cardiovascular disease than
the normal population.
19,20
In addition, although blood pressure
decreases after removal of the obstruction, a high proportion of
these patients develop persistent hypertension.
19,21-23
Conclusions
The timely diagnosis of critical coarctation of the aorta in
neonates is difficult, and data from Scandinavia, Europe and
the USA show how poorly this is done. Delayed diagnosis also
occurs in older patients, despite the ease of diagnosis.
These problems are likely to be worse in Africa with a widely
dispersed largely rural population and a shortage of medical
resources. Furthermore, with the high average birth rate in
Africa, the present population of 1.2 billion is expected to
double by 2050, thereby increasing the number of children born
with congenital heart disease in general and coarctation of the
aorta in particular.
Nevertheless, attempts should be made to diagnose and treat
coarctation of the aorta at any age, especially because diagnosis
needs only good physical examination. Treatment of coarctation
of the aorta is cheaper, easier, and results are better than for
most other forms of critical congenital heart disease, and most
patients do well after the obstruction is removed.
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